Removes assertion for file downloads
Removes assertion for file downloads

Selenium driver has no support for checking `status_code` or
`response_headers`.
I've failed to find a reliable way to check for file downloads. My
understanding so far is that there are 2 possible outcomes:
1. File opens in a new window, and so I could check for a new
window handle. Which isn't ideal, but still something:
```ruby
page.driver.browser.window_handles.size >= 2
```

2. File downloads to the local filesystem. In this case I could
do an additional visit statement and check for the presence of
downloaded file.
```ruby
visit 'file:///home/seluser/Downloads/'
expect(page).to have_link('downloaded_file')
```
This is not reliable right now since my docker image isn't clearing
downloaded files from previous sessions and that can cause false
positives.

ndlib/QA_tests,ndlib/QA_tests,ndlib/QA_tests